Resin composition whose lubricity under wet conditions is maintained

ABSTRACT

Provided is a resin composition which has excellent lubricity and a good touch feeling under wet conditions and suffers from little deterioration in the lubricity or the good touch feeling even if used repeatedly, and is excellent in flexibility. More specifically, the resin composition contains 100 parts by mass of a water-absorbing polymer and 60 to 500 parts by mass of a thermoplastic resin that has a type D durometer hardness (HDD) of 10 to 60.

1. TECHNICAL FIELD

The present invention relates to a resin composition whose lubricityunder wet conditions is maintained. More particularly, the presentinvention relates to a resin composition obtained by mixing awater-absorbing modified polyalkylene oxide with a thermoplastic resin.

2. BACKGROUND ART

There has heretofore been proposed a razor blade cartridge in which awater-soluble resin such as a polyalkylene oxide is attached, penetratedor dispersed in a part of a razor blade cartridge made of plastic inorder to reduce the resistance between a part of a razor and the face orthe like (Patent Document 1).

Moreover, some composites in which a water-absorbing resin is swollen torelease a variety of aids upon immersion in water, due to mixing of awater-soluble resin and a water-absorbing resin, have been used in asmoother for wet shaving (Patent Document 2).

In addition, as a polymer composite used for wet shaving instruments andmedical instruments, a polymer composite containing a water-insolublepolymer, and a water-sensitive copolymer polymerized from an alkyleneoxide monomer and an epoxy-functional monomer has been disclosed (PatentDocument 3).

PRIOR ART DOCUMENTS Patent Documents

-   Patent Document 1: JP 54-94961 A-   Patent Document 2: JP 9-502632 A-   Patent Document 3: JP 2004-509207 A

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

The razor blade cartridge described in Patent Document 1, the compositedescribed in Patent Document 2, and the polymer composite described inPatent Document 3 give lubricity to a surface of the composite or thelike utilizing dissolution of a water-soluble resin such as apolyalkylene oxide under wet conditions.

However, the water-soluble resin has low compatibility with athermoplastic resin or the like and is merely scattered on a surface ofthe composite or the like in a massive form. For this reason, lubricityat the initial stage of use is excellent, but the scatteredwater-soluble resin is dropped in a massive form by repeated used, andthe lubricity is lost in a short term.

In addition, generally, in a water-soluble resin such as a polyalkyleneoxide, lubricity is improved as the molecular weight increases, butcobwebbing under wet conditions becomes remarkable and, further, themelt viscosity thereof becomes high. Therefore, it is necessary to raisethe temperature upon processing. For this reason, the resin is oftenmixed with a hard resin such as a high impact polystyrene or apolystyrene having a high processing temperature, and the hardness ofthe resulting resin composition is high. Therefore, there is a problemthat, when the resin is mounted on, for example, a razor requiringflexibility that is equipped with a bendable blade in order to fit withthe skin, the resin is cracked upon bending.

On the other hand, when the water-soluble resin is mixed with resinsobtained by copolymerizing a rubber component having flexibility, sincethese resins have to be processed at a low temperature, there is aproblem that the water-soluble resin such as a polyalkylene oxide cannotbe sufficiently molten and is brought into a state where thewater-soluble resin such as the polyalkylene oxide is scattered in acomposition, and not only design characteristics and lubricity uponrepeated use are deteriorated, but also objective flexibility issuppressed.

An object of the present invention is to provide a resin compositionwhich has excellent lubricity and a good touch feeling under wetconditions and suffers from little deterioration in the lubricity or thegood touch feeling even if used repeatedly, and is excellent inflexibility.

Means for Solving the Problems

The present inventors studied earnestly in order to solve theabove-described problems and found that a resin composition containing awater-absorbing modified polyalkylene oxide and a thermoplastic resinhaving a type D durometer hardness (HDD) of 10 to 60 is excellent inlubricity, does not lose its lubricity even if used repeatedly, and hasflexibility. Thus, they have accomplished the present invention.

That is, the present invention relates to a resin composition whichmaintains excellent lubricity and a good touch feeling even if usedrepeatedly, and has flexibility. More particularly, the presentinvention relates to a resin composition containing 100 parts by mass ofa water-absorbing modified polyalkylene oxide and 60 to 500 parts bymass of a thermoplastic resin having a type D durometer harness (HDD) of10 to 60.

Effects of the Invention

Since the resin composition of the present invention does not loselubricity and a good touch feeling even if used repeatedly, and is alsoexcellent in flexibility, it can be widely used in wet shavinginstruments represented by a razor, and medical instruments such as acatheter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing a method of obtaining a meancoefficient of friction (MIU).

FIG. 2 is a schematic view showing a method of obtaining a deviation inmean coefficient of friction (MMD).

MODE FOR CARRYING OUT THE INVENTION

The resin composition of the present invention is obtained by mixing awater-absorbing modified polyalkylene oxide with a thermoplastic resinhaving a type D durometer hardness (HDD) of 10 to 60.

The water-absorbing modified polyalkylene oxide used in the resincomposition of the present invention is, for example, a modifiedpolyalkylene oxide obtained by reacting a polyalkylene oxide compound, adiol compound and a diisocyanate compound. Such a modified polyalkyleneoxide has thermoplasticity. For this reason, the modified polyalkyleneoxide has good compatibility with a thermoplastic resin, and a resincomposition having flexibility can be obtained.

As the polyalkylene oxide compound, a polyalkylene oxide compound having90% by mass or more of ethylene oxide groups is preferable, and apolyalkylene oxide compound having 95% by mass or more of ethylene oxidegroups is more preferable. When the amount of ethylene oxide groups isless than 90% by mass, there is a possibility that lubricity at theinitial stage of the resulting resin composition is deteriorated.

As the polyalkylene oxide compound, a polyalkylene oxide compound havinga number average molecular weight of 5,000 to 50,000 is preferable, anda polyalkylene oxide compound having a number average molecular weightof 10,000 to 30,000 is more preferable. When a polyalkylene oxidecompound having a number average molecular weight of less than 5,000 isused, there is a possibility that lubricity at the initial stage of theresulting resin composition is deteriorated. When a polyalkylene oxidecompound having a number average molecular weight of more than 50,000 isused, there is a possibility that the melt viscosity of the resultingwater-absorbing modified polyalkylene oxide is high, compatibility witha thermoplastic resin is deteriorated, and it becomes difficult tomaintain lubricity upon repeated use.

Examples of the diol compound include ethylene glycol, diethyleneglycol, triethylene glycol, tetraethylene glycol, propylene glycol,dipropylene glycol, trimethylene glycol, 1,3-butanediol, 2,3-butanediol,1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol and 1,9-nonanediol.Among these diol compounds, from the viewpoints that the resultingwater-absorbing modified polyalkylene oxide is excellent in the waterabsorption ability, that elution of a water-soluble component issuppressed, and that stability is excellent, ethylene glycol and1,4-butanediol are preferably used. These diol compounds may each beused alone, or two or more kinds may be used in combination.

The proportion of use of the diol compound is preferably 0.8 to 2.5 mol,more preferably 1.0 to 2.0 mol based on 1 mol of the polyalkylene oxidecompound. When the proportion of use of the diol compound is less than0.8 mol, there is a possibility that lubricity cannot be maintained whenthe resulting resin composition is used repeatedly. On the other hand,when the proportion of use of the diol compound is more than 2.5 mol,there is a possibility that lubricity at the initial stage of theresulting resin composition is deteriorated. The molar number of thepolyalkylene oxide compound can be obtained by dividing the mass thereofby the number average molecular weight thereof.

The diisocyanate compound is not particularly limited as far as it is acompound having two isocyanate groups (—NCO) in the same molecule, andexamples thereof include 4,4′-diphenylmethane diisocyanate (MDI),1,6-hexamethylene diisocyanate (HDI),dicyclohexylmethane-4,4′-diisocyanate (HMDI),3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (IPDI),1,8-dimethylbenzol-2,4-diisocyanate, and 2,4-tolylene diisocyanate(TDI). Among these diisocyanate compounds, from the viewpoints ofcompatibility with a thermoplastic resin, suppression of elution of awater-soluble compound, and excellent stability,dicyclohexylmethane-4,4′-diisocyanate (HMDI) and 1,6-hexamethylenediisocyanate (HDI) are preferably used. These diisocyanate compounds mayeach be used alone, or two or more kinds may be used in combination.

The proportion of use of each of the polyalkylene oxide compound, thediol compound and the diisocyanate compound is determined so that theratio of the molar number of isocyanate groups of the diisocyanatecompound relative to the total molar number of terminal hydroxyl groupsof the polyalkylene oxide compound and hydroxyl groups of the diolcompound [R value=(—NCO group/—OH group)] is preferably in the range of0.7 to 1.2, more preferably in the range of 0.8 to 1.05. When the Rvalue is less than 0.7, there is a possibility that the resultingwater-absorbing modified polyalkylene oxide is water-soluble, andlubricity cannot be maintained when the resulting resin composition isused repeatedly. On the other hand, when the R value is more than 1.2,there is a possibility that the melt viscosity of the resultingwater-absorbing modified polyalkylene oxide becomes high, andcompatibility with a thermoplastic resin is deteriorated. The molarnumber of the polyalkylene oxide compound can be obtained by dividingthe mass thereof by the number average molecular weight thereof.

Examples of a method of reacting the polyalkylene oxide compound, thediol compound and the diisocyanate compound include: a method ofdissolving or dispersing the compounds in a reaction solvent such astoluene, xylene, or dimethylformamide to react; and a method ofuniformly mixing these compounds in a powder state or a solid state, andheating the mixture to a predetermined temperature to react. From theviewpoint of industrial implementation, a method of continuously feedingraw materials in a molten state, and mixing the raw materials in amulti-screw extruder to react is preferable. The temperature of thereaction is preferably 70 to 210° C.

When the water-absorbing modified polyalkylene oxide is produced, fromthe viewpoint of promoting a reaction, a small amount of triethylamine,triethanolamine, dibutyltin dilaurate, dioctyltin dilaurate, tin2-ethylhexanoate, triethylenediamine or the like can also be added to areaction system.

Thus, by reacting the polyalkylene oxide compound, the diol compound andthe diisocyanate compound, a water-absorbing modified polyalkylene oxidecan be obtained.

The melt viscosity of the water-absorbing modified polyalkylene oxideused in the resin composition of the present invention, when measuredusing a flow tester (condition: 170° C., 5.0 MPa, a die having adiameter of 1 mm and a length of 1 mm is used), is preferably 100 to 800[Pa·s], more preferably 200 to 600 [Pa·s]. When the melt viscosity isless than 100 [Pa·s], there is a possibility that lubricity at theinitial stage of the resulting resin composition is deteriorated. Whenthe melt viscosity is more than 800 [Pa·s], there is a possibility thatcompatibility with a thermoplastic resin is deteriorated.

The water absorption ability of the water-absorbing modifiedpolyalkylene oxide used in the resin composition of the presentinvention is preferably 10 to 40 [g/g], more preferably 15 to 35 [g/g].When the water absorption ability of the water-absorbing modifiedpolyalkylene oxide is less than 10 [g/g], there is a possibility thatlubricity at the initial stage of the resulting resin composition isdeteriorated. When the water absorption ability of the water-absorbingmodified polyalkylene oxide is more than 40 [g/g], there is apossibility that lubricity cannot be maintained when the resulting resincomposition is used repeatedly. In the present invention, the waterabsorption ability is a value measured by a method described later.

The ratio of water-soluble component of the water-absorbing modifiedpolyalkylene oxide used in the present invention, from the viewpoint ofimproving the lubricity of the resulting resin composition, ispreferably 5 to 30% by mass, more preferably 10 to 20% by mass. When thewater-soluble component of the water-absorbing modified polyalkyleneoxide is less than 5% by mass, there is a possibility that lubricity atthe initial stage is deteriorated. When the water-soluble component ofthe water-absorbing modified polyalkylene oxide is more than 30%, thereis a possibility that lubricity cannot be maintained when the resultingresin composition is used repeatedly. The ratio of water-solublecomponent in the present invention is a value measured by a methoddescribed later.

The thermoplastic resin used in the resin composition of the presentinvention has a type D durometer hardness (HDD) of 10 to 60, preferably20 to 50. When the HDD is less than 10, a force returning to theoriginal shape (restoring force) is reduced when a force is applied tothe resulting resin composition. When the HDD is more than 60, if theresulting resin composition is bent, the bent part is whitened and doesnot return to the original shape, and lubricity cannot be maintainedwhen the resin composition is used repeatedly.

Examples of the thermoplastic resin having an HDD of 10 to 60 include anethylene/methacrylic acid copolymer, an ethylene/vinyl acetatecopolymer, an ethylene/acrylic acid copolymer, an ethylene/ethylacrylate copolymer, and an acrylonitrile/butadiene/styrene copolymer(ABS). Among these thermoplastic resins, from the viewpoint that theresin has good compatibility with the water-absorbing modifiedpolyalkylene oxide, an ethylene/vinyl acetate copolymer, anethylene/acrylic acid copolymer, and an ethylene/ethyl acrylatecopolymer are preferably used. These thermoplastic resins may each beused alone, or two or more kinds may be used in combination.

The proportion of use of the thermoplastic resin having an HDD of 10 to60 is 60 to 500 parts by mass, preferably 100 to 300 parts by massrelative to 100 parts by mass of the water-absorbing modifiedpolyalkylene oxide. When the proportion of use of the thermoplasticresin is less than 60 parts by mass, there is a problem that, when theresulting resin composition is contacted with water, the swelling ratioin water is high, the dimension is greatly changed by dilation and, forexample, the resin is dropped from a razor blade cartridge. On the otherhand, when the proportion of use of the thermoplastic resin is more than500 parts by mass, lubricity at the initial stage of the resulting resincomposition is deteriorated.

Examples of a method for producing the resin composition of the presentinvention include 1) a method of mixing the water-absorbing modifiedpolyalkylene oxide with the thermoplastic resin having an HDD of 10 to60 using a mixing machine such as a Henschel mixer or a blender, orsupplying a predetermined amount of each of them to a kneader, a roll,an extruder or the like with a metering feeder, and melt-mixing them,and 2) a method of reacting the polyalkylene oxide, the diol compoundand the diisocyanate compound in the thermoplastic resin having an HDDof 10 to 60, which has been molten in advance.

As an instrument in which the melting, the melt-mixing, or the reactionis performed, from the viewpoint that mixability of the components isexcellent, a twin-screw extruder is preferably used.

After the melt-mixing or the reaction, the melt may be molded into adesired shape such as a pellet, a sheet (in the present description, thesheet refers to a sheet having a thickness of 0.2 mm or more), a film(in the present description, the film refers to a film having athickness of less than 0.2 mm), a bar, or a fiber by performinginjection molding, extrusion molding or inflation molding.

When the resin composition of the present invention is produced, fromthe viewpoint of preventing degradation of the components or theresulting resin composition, a stabilizer; from the viewpoint ofimproving weather resistance of the resulting resin composition, a UVabsorber; from the viewpoint of coloring the resulting resincomposition, a pigment, a coloring material etc.; from the viewpoint ofimparting foamability to the resulting resin composition, a soapmaterial; and the like may be added.

From the viewpoint that processing at a low temperature is easy, theresin composition of the present invention can be mixed with a drugwhich is easily thermally degraded such as ascorbic acid, sodiumascorbate, or ethylascorbic acid. The resin composition with such a drugadded thereto can effectively release the drug when contacted withwater. The amount of addition of the drug is preferably 0.05 to 5.0parts by mass, more preferably 0.1 to 3.5 parts by mass based on 100parts by mass of the resin composition. When the amount of addition ofthe drug is less than 0.05 parts by mass, the amount of drug to bereleased from the resulting resin composition is small, and there is apossibility that the effect of the drug is not exerted. When the amountof addition of the drug is more than 5.0 parts by mass, there is apossibility that a surface of the resin composition is roughened to bebrought into an irregular state, and not only smoothness is reduced butalso control of the release amount of the drug becomes impossible.

The present invention will be described in more detail by way ofexamples and comparative examples, but the present invention is notlimited thereto.

[Evaluation Methods]

The water absorption ability and the ratio of water-soluble component ofthe modified polyalkylene oxide and the cross-linked polyacrylatedescribed in production examples, the melt viscosity of the modifiedpolyalkylene oxide, the type D durometer hardness (HDD) of thethermoplastic resin used in examples, as well as the bending test,swelling ratio, slimy feeling and friction physical properties of theresin composition obtained in examples and comparative examples weremeasured and evaluated according to the following methods.

(1) Water Absorption Ability

The water absorption ability of the modified polyalkylene oxide and thecross-linked polyacrylate were measured by the following method.

About 1 [g] of the modified polyalkylene oxide or the cross-linkedpolyacrylate was weighed (A [g]), and immersed in 100 [mL] of ionexchange water measured in a 200 mL beaker at room temperature (22° C.)for 24 hours to gel. Thereafter, the gel was filtered with a wire gauzeof 200 meshes (pore size: 75 μm), the mass thereof (B [g]) was measured,and the water absorption ability was calculated by the followingequation.

Water absorption ability[g/g]=B/A

(2) Ratio of Water-Soluble Component

A gel obtained by the measurement of (1) Water absorption ability wasdried in a hot air dryer set at 105° C. to a constant weight [C (g)],and the ratio of water-soluble component was calculated by the followingequation, provided that A is the same as A in the measurement of (1)Water absorption ability.

Ratio of water-soluble component[mass %]=(A−C)/A×100

(3) Melt Viscosity

1.5 g of the modified polyalkylene oxide or the like was measured usinga flow tester (Model: CFT-500C, manufactured by Shimadzu Corporation)under the following conditions.

Load: 5.0 MPa

Measurement temperature: 170° C.

Die diameter: 1 mm

Die length: 1 mm

(4) Type D Durometer Hardness (HDD)

The type D durometer hardness (HDD) means the “hardness” measured in“type D durometer hardness” in accordance with “Method of testingdurometer hardness of plastic” described in Japanese IndustrialStandard: JIS K 7215 (1986).

Specifically, after confirming that the flatness and parallelism of asheet surface or a film surface of a molded resin composition were good,a plurality of sheets or films were piled so that the whole thickness(T) became 6 mm or more, and this was used as a measurement sample.After confirming that adherability between a plurality of sheets orfilms was good, the HDD of the resulting measurement sample was measuredon a durometer holder.

(5) Bending Test

Sheets or films of resin compositions obtained in examples andcomparative examples were each cut into 2 cm (width: W)×5 cm (length:L), and these were used as measurement samples.

Each measurement sample was bent at 90 degrees at a part 1 cm from anend (short side of 2 cm in width) of the measurement sample (the rest: 4cm), and the bent part was evaluated in accordance with the followingcriteria. In addition, separately, using the same measurement samplesand changing the bending angle to 180 degrees, the same evaluation wasperformed.

Evaluation Criteria

A: A bent part is not whitened and returns to the original sheet shapeor film shape (presence of a restoring force).

B: A bent part is whitened but returns to the original sheet shape orfilm shape (presence of restoring force).

C: There is whitening at a bent part, and the bent part does not returnto the original sheet shape or film shape (absence of restoring force).

(6) Swelling Ratio (a) Swelling Ratio of Sheet

Sheets of resin compositions obtained in examples and comparativeexamples were each cut into 2 cm (W)×5 cm (L), and these were used asmeasurement samples.

The mass (E [g]) of each measurement sample was measured, and the samplewas immersed in 100 [mL] of ion exchange water measured in a 200 mLbeaker at room temperature (22° C.) for 24 hours to swell. Thereafter,the measurement sample was taken out, water on the sample surface waswiped using a paper towel, and the mass (F [g]) thereof was measured.When the swelling ratio is less than 300%, it can be judged that thechange in dimension due to swelling is small. When a gel-likewater-absorbing resin was desorbed from a swollen resin composition,this was evaluated as “gel desorption”.

Swelling ratio[%]=(F−E)/E×100

(b) Swelling Ratio of Film

Separately, films of resin compositions obtained in examples andcomparative examples were each cut into 2 cm (W)×5 cm (L), and thesewere used as measurement samples.

The mass (E [g]) of each measurement sample was measured, and the samplewas immersed in 100 [mL] of ion exchange water measured in a 200 mLbeaker at room temperature (22° C.) for 1 minute to swell. Themeasurement sample was taken out, water on the sample surface was wipedusing a paper towel, and the mass (F [g]) thereof was measured. When theswelling ratio is less than 200%, it can be judged that the change indimension due to swelling is small. When a gel-like water-absorbingresin was desorbed from a swollen resin composition, this was evaluatedas “gel desorption”.

Swelling ratio[%]=(F−E)/E×100

(7) Slimy Feeling

Sheets or films of the resin compositions obtained in examples andcomparative examples were each cut into 2 cm (W)×5 cm (L), and thesewere used as measurement samples.

Each measurement sample obtained in an example or the like was immersedin 100 mL of ion exchange water measured in a 200 mL beaker for 1minute, water on a sample surface was wiped with a paper towel, and asurface of the measurement sample was rubbed with a hand, followed byevaluation according to the following evaluation criteria.

Evaluation Criteria

A: No slimy feeling was felt.

B: No cobwebbing occurred but slimy feeling was felt.

C: Slimy feeling was felt and cobwebbing occurred.

(8) Friction Physical Property

Sheets or films of the resin compositions obtained in examples andcomparative examples were each cut into 2 cm (W)×5 cm (L), and thesewere used as measurement samples.

After 30 seconds from dropping 0.2 mL of ion exchange water onto acoating surface of each of the measurement sample, the coefficient offriction μ was monitored using a friction tester (Model: KES-SE,manufactured by KATO TECH CO., LTD.) under the following testconditions.

Sensor: silicone

Load: 50 [g]

Speed: 5 [mm/sec]

(i) Mean Coefficient of Friction (MIU)

The mean coefficient of friction has correlation with ease of slippingor resistance to slipping when rubbing the surface. The larger the valueis, the more difficult the surface is to slip.

A schematic view of obtaining a mean coefficient of friction (MIU) fromthe monitored result of the coefficient of friction μ is shown in FIG.1.

As shown in FIG. 1, a surface of a measurement sample is scanned tomonitor the coefficient of friction μ of a surface. Then, thecoefficient of friction μ is integrated at a monitored width of 20 mm(shadow area of FIG. 1). By dividing the integrated value by themonitored width (20 mm), the mean coefficient of friction (MIU) isobtained.

When the value of MIU is 0.3 or less, it can be said that the slippingproperty is good.

(ii) Deviation in Mean Coefficient of Friction (MMD)

The deviation in mean coefficient of friction has correlation withsmoothness and roughness when rubbing the surface. The larger this valueis, the rougher the surface is.

A schematic view of obtaining a deviation in mean coefficient offriction (MMD) from the monitored result of the coefficient of frictionis shown in FIG. 2

As shown in FIG. 2, an absolute value of a difference between the meancoefficient of friction (MIU) and the coefficient of friction μ isintegrated at a monitored width of 20 mm (shadow area of FIG. 2). Adeviation in mean coefficient of friction (MMD) is obtained by dividingthe integrated value by the monitored width (20 mm).

When the value of MMD is 0.015 or less, it can be said that thesmoothness of the surface is good.

(iii) Repetition Test

After first monitoring, water on a surface was wiped with a paper towel,and a sheet or a film was placed in an oven set at 50° C. to dry. Then,second monitoring was performed under the same conditions as describedabove. Similarly, the monitoring was repeated up to 6 times, and thecoefficient of friction μ was monitored.

(9) Drug Release Amount

A sheet or a film of the resulting resin composition was cut into arectangular shape of 2 cm (W)×5 cm (L)×0.1 cm (T) (mass: 1.0 g), andimmersed in 10 g of water for a predetermined time (10, 20, 30, and 60minutes).

The water (4.5 mL) after the sheet or the film was taken out was placedin quartz glass having a thickness of 1 cm and the absorbance at awavelengths of 289 nm was measured using an ultraviolet-visiblespectrophotometer (Model: UV-3150, manufactured by ShimadzuCorporation). Using the resulting absorbance, the amount of extractedascorbic acid was calculated from a calibration curve of ascorbic acidwhich had been measured in advance under the same conditions.

Production Example 1 Method for Producing Water-Absorbing ModifiedPolyalkylene Oxide

A storage tank A equipped with a stirrer and held at 80° C. was chargedwith 100 parts by mass of a fully dehydrated polyethylene oxide having anumber average molecular weight of 20,000, 0.90 parts by mass of1,4-butanediol and 0.1 parts by mass of dioctyltin dilaurate, followedby stirring under a nitrogen gas atmosphere to obtain a uniform mixture.Separately, a storage tank B held at 30° C. was charged withdicycrohexylmethane-4,4′-diisocyanate and the tank was stored under anitrogen gas atmosphere.

Using a metering pump, the mixture of the storage tank A wascontinuously supplied at a rate of 500 [g/min] anddicyclohexylmetahane-4,4′-disisocyanate of the storage tank B wascontinuously supplied at a rate of 19.4 [g/min] to a twin-screw extruderset at 110 to 140° C. (R value=1.00), the materials were mixed in theextruder to perform a reaction, a strand was discharged through anopening of the extruder, and pelletized with a pelletizer to obtain awater-absorbing modified polyalkylene oxide.

The resulting water-absorbing modified polyalkylene oxide had a waterabsorption ability of 25 [g/g], a proportion of water-soluble componentof 15.5 [mass %], and a melt viscosity of 320 [Pa·s].

Production Example 2 Method for Producing Water-Absorbing ModifiedPolyalkylene Oxide

An ethylene oxide/propylene oxide (mass ratio: 90/10) copolymer having anumber average molecular weight of 15,000 was supplied at a rate of 250[g/min] and ethylene glycol heated to 40° C. was supplied at a rate of2.1 [g/min] to a 40 mm-diameter single-screw extruder (L/D=40, presettemperature: 90° C.), respectively, which were then melt-mixed.

The mixture obtained from a discharging opening (the mixture wasdischarged in a uniform, molten state, and it was confirmed by LCanalysis that the materials were mixed in a charged ratio) wascontinuously supplied to a hopper port (preset temperature: 80° C.) of a30 mm-diameter twin-screw extruder (L/D=41.5). At the same time,dioctyltin dilaurate was supplied to the hopper port of the twin-screwextruder at a rate of 0.5 [g/min].

Separately, dicyclohexylmethane-4,4′-diisocyanate adjusted to 30° C. wassupplied to a screw barrel section situated on a downstream side of thehopper port of the twin-screw extruder at a rate of 12.4 [g/min] (Rvalue=0.95) and a reaction was carried out continuously under a nitrogenatmosphere (preset temperature: 180° C.). A strand obtained from anopening of the twin-screw extruder was cooled, and then pelletized witha pelletizer to obtain a water-absorbing modified polyalkylene oxide.

The resulting water-absorbing modified polyalkylene oxide had a waterabsorption ability of 20 [g/g], a proportion of water-soluble componentof 11.3 [mass %], and a melt viscosity of 150 [Pa·s].

Production Example 3 Method for Producing Water-Soluble ModifiedPolyalkylene Oxide

A polyethylene oxide having a number average molecular weight of 20,000was supplied to a 40 mm-diameter single-screw extruder (L/D=40, presettemperature: 90° C.) at a rate of 250 [g/min] and molten.

The melt obtained from a discharge port was continuously supplied to ahopper port (preset temperature: 80° C.) of a 30 mm-diameter twin-screwextruder (L/D=41.5). At the same time, dioctyltin dilaurate was suppliedto the hopper port of the twin-screw extruder at a rate of 0.25 [g/min].

Separately, dicyclohexylmethane-4,4′-diisocyanate adjusted to 30° C. wassupplied to a screw barrel section situated on a downstream side of thehopper port of the twin-screw extruder at a rate of 3.27 [g/min] (Rvalue=1.00) and a reaction was carried out continuously under a nitrogenatmosphere (preset temperature: 180° C.). A strand obtained from anopening of the twin-screw extruder was cooled, and then pelletized witha pelletizer to obtain a water-soluble modified polyalkylene oxide.

The resulting water-absorbing modified polyalkylene oxide had aproportion of water-soluble component of 100 [mass %] and a meltviscosity of 220 [Pa·s]. Since the resulting modified polyalkylene oxidewas water-soluble, the water absorption ability could not be measured.

Production Example 4 Method for Producing Cross-Linked Polyacrylate

To a 1 L four-necked cylindrical round-bottom flask equipped with astirrer, a reflux condenser and a nitrogen gas inlet tube was added 550mL of n-heptane. In this was added and dispersed 1.38 g of hexaglycerylmonobeherate (surfactant: NONION GV-106 manufactured by NOF Corporation)having an HLB of 13.1, and the temperature was raised to 50° C. todissolve the surfactant, followed by cooling to 30° C.

Meanwhile, a 500 mL Erlenmeyer flask was separately prepared, and 92 gof a 80 mass % aqueous acrylic acid solution was added thereto. To thiswas added dropwise 152.6 g of a 20.1 mass % aqueous sodium hydroxidesolution while cooling from the outside to perform neutralization of 75mol %, thereafter, 0.11 g of potassium persulfate and 0.019 g ofethylene glycol diglycidyl ether as a crosslinking agent were furtheradded and dissolved. Thereby, an aqueous solution of partiallyneutralized acrylic acid was obtained.

Then, the whole of the aqueous solution of partially neutralized acrylicacid was added and dispersed in the four-necked cylindrical round bottomflask, the system was replaced with nitrogen, the temperature wasraised, and a polymerization reaction was performed over 3 hours whilethe temperature of the bath was retained at 70° C.

After completion of the polymerization reaction, a slurry containing theresulting cross-linked polyacrylate was dried at 120° C. for 2 hours toobtain 191.2 g of a cross-linked polyacrylate.

The resulting cross-linked polyacrylate had a water absorption abilityof 550 [g/g] and a proportion of water-soluble component of 0.06 [%].The melt viscosity of the resulting cross-linked polyacrylate could notbe measured.

Example 1

6 [kg/hr] of a water-absorbing modified polyalkylene oxide obtained asin Production Example 1 and 15 [kg/hr] of an ethylene/vinyl acetatecopolymer [abbreviation: EVA, manufactured by Sumitomo Chemical Co.,Ltd.: Evatate D3010, vinyl acetate content=10%, melt index (MI)=6,HDD=35] were supplied to a 28 mm-diameter twin-screw extruder (L/D=40)set at 130° C. to obtain a resin composition. The compositional ratio ofthe resin composition is shown in Table 1.

The resulting resin composition was molded into a 6 cm (W)×9 cm (L)×0.15cm (T) sheet of the resin composition using an injection-molding machine(Model: TI80G2, manufactured by Toyo Machinery and Metal Co., Ltd.) setat 130 to 150° C.

The resulting sheet of the resin composition was cut into apredetermined size and the above-described various measurements andevaluations were performed. The results are shown in Table 2.

Example 2

7 [kg/hr] of a water-absorbing modified polyalkylene oxide obtained asin Production Example 1 and 14 [kg/hr] of an ethylene/acrylic acidcopolymer [abbreviation: EAA, manufactured by Dow Chemical: Primacor5980, acrylic acid content=20%, MI=300, HDD=40] were supplied to a 28mm-diameter twin-screw extruder (L/D=40) set at 140° C. to obtain aresin composition. The compositional ratio of the resin composition isshown in Table 1.

The resulting resin composition was molded into a 10 cm (W)×10 cm(L)×0.10 cm (T) sheet of the resin composition using a hot press(manufactured by Gonno Hydraulic Press, 40 t press, pressure: 50[kg/cm²]) set at 130° C.

The resulting sheet of the resin composition was cut into apredetermined size, and the above-described various measurements andevaluations were performed. The results are shown in Table 2.

Example 3

10 [kg/hr] of a water-absorbing modified polyalkylene oxide obtained asin Product Example 2 and 10 [kg/hr] of an ethylene/acrylic acidcopolymer [abbreviation: EAA, manufactured by Dow Chemical: Primacor3460, acrylic acid content=9.7%, MI=20, HDD=42] were supplied to a 28mm-diameter twin-screw extruder (L/D=40) set at 130° C. to obtain aresin composition. The compositional ratio of the resin composition isshown in Table 1.

The resulting resin composition was molded into a 10 cm (W)×10 cm(L)×0.10 cm (T) sheet of the resin composition using a hot press(manufactured by Gonno Hydraulic Press, 40 t press, pressure: 50[kg/cm²]) set at 130° C.

The resulting sheet of the resin composition was cut into apredetermined size, and the above-described various measurements andevaluations were performed. The results are shown in Table 2.

Example 4

6 [kg/hr] of a water-absorbing modified polyalkylene oxide obtained asin Product Example 1, 12 [kg/hr] of an ethylene/vinyl acetate copolymer[abbreviation: EVA, manufactured by Sumitomo Chemical Co., Ltd.: EvatateD2010, vinyl acetate content=25%, MI=3, HDD=28], and 3 [kg/hr] of anethylene/acrylic acid copolymer [abbreviation: EAA, manufactured by DowChemical: Primacor 3460, acrylic acid content=9.7%, MI=20, HDD=42] weresupplied to a 28 mm-diameter twin-screw extruder (L/D=40) set at 140°C., respectively, to obtain a resin composition. The compositional ratioof the resin composition is shown in Table 1.

The resulting resin composition was molded into a 10 cm (W)×10 cm(L)×0.10 cm (T) sheet of the resin composition using a hot press (GonnoHydraulic Press, 40 t press, pressure: 50 [kg/cm²]) set at 130° C.

The resulting sheet of the resin composition was cut into apredetermined size, and the above-described various measurements andevaluations were performed. The results are shown in Table 2.

Example 5

5 [kg/hr] of a water-absorbing modified polyalkylene oxide obtained asin Production Example 2 and 8 [kg/hr] of an ethylene/ethyl acrylatecopolymer [abbreviation: EEA, manufactured by Nippon Unicar CompanyLimited: NUC-6170, ethyl acrylate content=18%, MI=6, HDD=31] weresupplied to a 28 mm-diameter twin-screw extruder (L/D=40) set at 150° C.to obtain a resin composition. The compositional ratio of the resincomposition is shown in Table 1.

The resulting resin composition was molded into a 10 cm (W)×10 cm(L)×0.10 cm (T) sheet of the resin composition using a hot press (GonnoHydraulic Manufacturing Co., Ltd, 40 t press, pressure: 50 [kg/cm²]) setat 150° C.

The resulting sheet of the resin composition was cut into apredetermined size, and the above-described various measurements andevaluations were performed. The results are shown in Table 2.

Example 6

6 [kg/hr] of a water-absorbing modified polyalkylene oxide obtained asin Production Example 1, 15 [kg/hr] of an ethylene/vinyl acetatecopolymer [abbreviation: EVA, manufactured by Sumitomo Chemical Co.,Ltd.: Evatate D3010, vinyl acetate content=10%, melt index (MI)=6, HDD35], and 42 [g/hr] of ascorbic acid were supplied to a 28 mm-diametertwin-screw extruder (L/D=40) set at 130° C. to obtain a resincomposition.

The resulting resin composition was processed into an inflation filmhaving a width of 160 mm and a thickness of 80 μm using an extruder(SYH25-25 manufactured by Silicone Machinery, L/D=25) set at 130 to 150°C. and an inflation molding machine (SF-300 manufactured by SiliconeMachinery).

The resulting inflation film was cut into a predetermined size, and theabove-described various measurements and evaluations were performed. Theresults are shown in Table 2.

Example 7

6 [kg/hr] of a water-absorbing modified polyalkylene oxide obtained asin Production Example 1, 15 [kg/hr] of an ethylene/vinyl acetatecopolymer [abbreviation: EVA, manufactured by Sumitomo Chemical Co.,Ltd.: Evatate D3010, vinyl acetate content=10%, melt index (MI)=6,HDD=35] and 42 [g/hr] (corresponding to 0.2 parts by mass based on 100parts by mass of a resin composition) of ascorbic acid were supplied toa 28 mm-diameter twin-screw extruder (L/D=40) set at 130° C. to obtain aresin composition. The compositional ratio of the resin composition isshown in Table 1.

The resulting resin composition was molded into a 6 cm (W)×9 cm (L)×0.15cm (T) sheet of the resin composition using an injection molding machine(Model: TI80G2, manufactured by Toyo Machinery and Metal Co., Ltd.) setat 130 to 150° C.

The resulting sheet of the resin composition was cut into apredetermined size, and the above-described various measurements andevaluations were performed. The results are shown in Tables 2 and 3.

Comparative Example 1

15 [kg/hr] of a water-absorbing modified polyalkylene oxide obtained asin Production Example 1 and 3 [kg/hr] of an ethylene/vinyl acetatecopolymer [abbreviation: EVA, manufactured by Sumitomo Chemical Co.,Ltd.: Evatate D3010, vinyl acetate content=10%, MI=6, HDD=35] weresupplied to a 28 mm-diameter twin-screw extruder (L/D=40) set at 120° C.to obtain a resin composition. The compositional ratio of the resincomposition is shown in Table 1.

The resulting resin composition was molded into a 6 cm (W)×9 cm (L)×0.15cm (T) sheet of the resin composition using an injection molding machine(Model: TI80G2, manufactured by Toyo Machinery and Metal Co., Ltd.) setat 130 to 150° C.

The resulting sheet of the resin composition was cut into apredetermined size, and the above-described various measurements andevaluations were performed. The results are shown in Table 2.

Comparative Example 2

6 [kg/hr] of a water-absorbing modified polyalkylene oxide obtained asin Production Example 1 and 15 [kg/hr] of an ethylene/vinyl acetatecopolymer [abbreviation: EVA, manufactured by DuPont-Mitsui PolychemicalCo., Ltd.: Evaflex EV45LX, vinyl acetate content=46%, MI=2.5, HDD=8]were supplied to a 28 mm-diameter twin-screw extruder (L/D=40) set at140° C. to obtain a resin composition. The compositional ratio of theresin composition is shown in Table 1.

The resulting resin composition was molded into a 6 cm (W)×9 cm (L)×0.15cm (T) sheet of the resin composition using an injection molding machine(Model: TI80G2, manufactured by Toyo Machinery and Metal Co., Ltd.) setat 130 to 150° C.

The resulting sheet of the resin composition was cut into apredetermined size, and the above-described various measurements andevaluations were performed. The results are shown in Table 2.

Comparative Example 3

6 [kg/hr] of a water-soluble polyethylene oxide (Model: PEO8Z,manufactured by Sumitomo Seika Chemicals Co., Ltd., viscosity averagemolecular weight: 2,000,000) and 15 [kg/hr] of an ethylene/vinyl acetatecopolymer [abbreviation: EVA, manufactured by Sumitomo Chemical Co.,Ltd.: Evatate D3010, vinyl acetate content=10%, MI=6, HDD=35] weresupplied to a 28 mm-diameter twin-screw extruder (L/D=40) set at 220° C.to obtain a resin composition. The compositional ratio of the resincomposition is shown in Table 1.

The resulting resin composition was molded into a 10 cm (W)×10 cm(L)×0.10 cm (T) sheet of the resin composition using a hot press(manufactured by Gonno Hydraulic Press, 40 t press, pressure: 50[kg/cm²]) set at 130° C.

The resulting sheet of the resin composition was cut into apredetermined size, and the above-described various measurements andevaluations were performed. The results are shown in Table 2.

Comparative Example 4

6 [kg/hr] of a water-soluble modified polyalkylene oxide obtained as inProduction Example 3 and 12 [kg/hr] of an ethylene/vinyl acetatecopolymer [abbreviation: EVA, manufactured by Sumitomo Chemical Co.,Ltd.: Evatate D3010, vinyl acetate content=10%, MI=6, HDD=35] weresupplied to a 28 mm-diameter twin-screw extruder (L/D=40) set at 130° C.to obtain a resin composition. The compositional ratio of the resincomposition is shown in Table 1.

The resulting resin composition was molded into a 6 cm (W)×9 cm (L)×0.15cm (T) sheet of the resin composition using an injection molding machine(Model: TI80G2, manufactured by Toyo Machinery and Metal Co., Ltd.) setat 130 to 150° C.

The resulting sheet of the resin composition was cut into apredetermined size, and the above-described various measurements andevaluations were performed. The results are shown in Table 2.

Comparative Example 5

2 [kg/hr] of a water-absorbing modified polyalkylene oxide obtained asin Production Example 2 and 18 [kg/hr] of an ethylene/acrylic acidcopolymer [abbreviation: EAA, manufactured by Dow Chemical: Primacor3460, acrylic acid content=9.7%, MI=20, HDD=42] were supplied to a 28mm-diameter twin-screw extruder (L/D=40) set at 130° C. to obtain aresin composition. The compositional ratio of the resin composition isshown in Table 1.

The resulting resin composition was molded into a 10 cm (W)×10 cm(L)×0.10 cm (T) sheet of the resin composition using a hot press(manufactured by Gonno Hydraulic Press, 40 t press, pressure: 50[kg/cm²]) set at 130° C.

The resulting sheet of the resin composition was cut into apredetermined size, and the above-described various measurements andevaluations were performed. The results are shown in Table 2.

Comparative Example 6

6 [kg/hr] of a water-absorbing modified polyalkylene oxide obtained asin Production Example 1 and 15 [kg/hr] of a high impact polystyrene[abbreviation: HIPS, manufactured by BASF: 476L, HDD=72] were suppliedto a 28 mm-diameter twin-screw extruder (L/D=40) set at 220° C. toobtain a resin composition. The compositional ratio of the resincomposition is shown in Table 1.

The resulting resin composition was molded into a 10 cm (W)×10 cm(L)×0.10 cm (T) sheet of the resin composition using a hot press(manufactured by Gonno Hydraulic Press, 40 t press, pressure: 50[kg/cm²]) set at 220° C.

The resulting sheet of the resin composition was cut into apredetermined size, and the above-described various measurements andevaluations were performed. The results are shown in Table 2.

Comparative Example 7

6 [kg/hr] of a cross-linked polyacrylate obtained in Production Example4 and 15 [kg/hr] of an ethylene/vinyl acetate copolymer [abbreviation:EVA: manufactured by Sumitomo Chemical Co., Ltd.: Evatate D3010, vinylacetate content=10%, MI=6, HDD=35] were supplied to a 28 mm-diametertwin-screw extruder (L/D=40) set at 120° C. to obtain a resincomposition. The compositional ratio of the resin composition is shownin Table 1.

The resulting resin composition was molded into a 10 cm (W)×10 cm(L)×0.10 cm (T) sheet of the resin composition using a hot press(manufactured by Gonno Hydraulic Press, 40 t press, pressure: 50[kg/cm²]) set at 130° C.

The resulting sheet of the resin composition was cut into apredetermined size, and the above-described various measurements andevaluations were performed. The results are shown in Table 2.

Comparative Example 8

15 [kg/hr] of a water-absorbing modified polyalkylene oxide obtain as inProduction Example 1 and 3 [kg/hr] of an ethylene/vinyl acetatecopolymer [abbreviation: EVA, manufactured by Sumitomo Chemical Co.,Ltd.: Evatate D3010, vinyl acetate content=10%, MI=6, HDD=35] weresupplied to a 28 mm-diameter twin-screw extruder (L/D=40) set at 120° C.to obtain a resin composition. The compositional ratio of the resincomposition is shown in Table 1.

The resulting resin composition was processed into an inflation filmhaving a width of 160 mm and a thickness of 80 μm using an extruder(SYH25-25, L/D=25, manufactured by Silicone Machinery) set at 130 to150° C. and an inflation molding machine (SF-300 manufactured bySilicone Machinery).

The resulting inflation film was cut into a predetermined size, and theabove-described various measurements and evaluations were performed. Theresults are shown in Table 2.

Comparative Example 9

6 [kg/hr] of a water-absorbing modified polyalkylene oxide obtained asin Production Example 1, 15 [kg/hr] of a high impact polystyrene[abbreviation: HIPS, manufactured by BASF: 476L, HDD=72] and 42 [g/hr](corresponding to 0.2 parts by mass based on 100 parts by mass of aresin composition) of ascorbic acid were supplied to a 28 mm-diametertwin-screw extruder (L/D=40) set at 220° C. to obtain a resincomposition. The compositional ratio of the resin composition is shownin Table 1.

The resulting resin composition was molded into a 10 cm (W)×10 cm(L)×0.1 cm (T) sheet of the resin composition using a hot press(manufactured by Gonno Hydraulic Press, 40 t press, pressure: 50[kg/cm²]) set at 220° C.

The resulting sheet of the resin composition was cut into apredetermined size, and the above-described various measurements andevaluations were performed. The results are shown in Tables 2 and 3.

TABLE 1 Modified polyalkylene oxide Different resin Thermoplastic resinSupply amount Supply amount Supply amount Kind [kg/hr] Kind [kg/hr] KindHDD [kg/hr] [Parts by mass]*⁾ Thickness Example 1 Production 6 — — EVA35 15 250 0.15 cm Example 1 Example 2 Production 7 — — EAA 40 14 2000.10 cm Example 1 Example 3 Production 10  — — EAA 42 10 100 0.10 cmExample 2 Example 4 Production 6 — — EVA 28 12 250 0.10 cm Example 1 EAA42 3 Example 5 Production 5 — — EEA 31 8 160 0.10 cm Example 2 Example 6Production 6 — — EVA 35 15 250   80 μm Example 1 Example 7 Production 6— — EVA 35 15 250 0.10 cm Example 1 Comparative Production 15  — — EVA35 3 20 0.15 cm Example 1 Example 1 Comparative Production 6 EVA 8 15250 0.15 cm Example 2 Example 1 Comparative — — PEO8Z 6 EVA 35 15 2500.10 cm Example 3 Comparative Production 6 — — EVA 35 12 200 0.15 cmExample 4 Example 3 Comparative Production 2 — — EAA 42 18 900 0.10 cmExample 5 Example 2 Comparative Production 6 — — HIPS 72 15 250 0.10 cmExample 6 Example 1 Comparative — — Production 6 EVA 35 15 250 0.10 cmExample 7 Example 4 Comparative Production 15  — — EVA 35 3 20   80 μmExample 8 Example 1 Comparative Production 6 — — HIPS 72 15 250 0.10 cmExample 9 Example 1 *⁾Parts by mass of a thermoplastic resin, letting awater-absorbing modified polyalkylene oxide or a different resin to be100 parts by mass

TABLE 2 Friction physical property Mean coefficient Deviation in meanSwelling of friction coefficient of Bending test ratio (MIU) friction(MMD) 90 degrees 180 degrees [%] Slimy feeling First time 6^(th) timeFirst time 6^(th) time Example 1 A A 180 A 0.18 0.22 0.009 0.014 Example2 A A 220 A 0.16 0.18 0.011 0.015 Example 3 A A 250 A 0.11 0.16 0.0090.013 Example 4 A A 190 A 0.09 0.21 0.009 0.012 Example 5 A A 280 A 0.140.17 0.010 0.014 Example 6 A A 150 A 0.18 0.22 0.009 0.014 Example 7 A A180 A 0.18 0.22 0.009 0.014 Comparative B C 560 A 0.15 0.35 0.014 0.017Example 1 Comparative C C 250 B 0.21 0.31 0.013 0.016 Example 2Comparative B C 190 C 0.75 0.81 0.069 0.089 Example 3 Comparative A A250 B 0.38 0.82 0.076 0.097 Example 4 Comparative A A  50 A 0.41 0.740.087 0.088 Example 5 Comparative C C 190 A 0.28 0.59 0.009 0.001Example 6 Comparative A A Gel A 0.67 0.77 0.098 0.115 Example 7desorption Comparative B C 150 A 0.15 0.35 0.014 0.017 Example 8Comparative C C 190 A 0.28 0.59 0.087 0.088 Example 9

As is apparent from the results shown in Table 2, the resin compositionof the present invention containing 100 parts by mass of awater-absorbing modified polyalkylene oxide and 60 to 500 parts by massof a thermoplastic resin having a type D durometer hardness (HDD) of 10to 60 has small change in dimension due to swelling, maintains itslubricity even if used repeatedly, has no slimy feeling, and hasflexibility.

TABLE 3 Immersion time Drug release amount [min] [mg] [mass %]*⁾ Example7 10 0.6 30 20 0.7 35 30 0.8 40 60 1.1 55 Comparative 10 0 0 Example 920 0 0 30 0 0 60 0 0 *⁾Amount (mass %) of release of 2 mg (amountcontained in 1 g of sheet of resin composition) of ascorbic acid inwater

As is apparent from the results shown in Table 3, it can be understoodthat the resin composition of the present invention containing 100 partsby mass of a water-absorbing modified polyalkylene oxide, 60 to 500parts by mass of a thermoplastic resin having a type D durometerhardness (HDD) of 10 to 60, and ascorbic acid (drug) can efficientlyrelease ascorbic acid into water without degradation by heat.

On the other hand, it can be understood that the resin composition ofComparative Example 8 cannot release the added ascorbic acid in waterbecause of degradation by heat, since it necessitates a high temperaturein the production stage.

INDUSTRIAL APPLICABILITY

Since the resin composition of the present invention maintains itslubricity even if used repeatedly, has no slimy feeling, and hasflexibility, it can be optimally used widely in the field requiringlubricity under wet conditions, for example, a wet shaving instrumentrepresented by a razor, and medical instruments such as a catheter.

1. A resin composition comprising 100 parts by mass of a water-absorbingmodified polyalkylene oxide and 60 to 500 parts by mass of athermoplastic resin having a type D durometer hardness (HDD) of 10 to60.
 2. The resin composition according to claim 1, wherein thewater-absorbing modified polyalkylene oxide is a modified polyalkyleneoxide obtained by reacting a polyalkylene oxide compound, a diolcompound and a diisocyanate compound.
 3. The resin composition accordingto claim 1, wherein the water-absorbing modified polyalkylene oxide hasa water absorption ability of 10 to 40 [g/g].
 4. The resin compositionaccording to claim 1, wherein the water-absorbing modified polyalkyleneoxide has a proportion of water-soluble component of 5 to 30% by mass.5. The resin composition according to claim 1, wherein the thermoplasticresin is an ethylene/vinyl acetate copolymer, an ethylene/acrylic acidcopolymer, an ethylene/ethyl acrylate copolymer or a combinationthereof.
 6. The resin composition according to claim 2, wherein thewater-absorbing modified polyalkylene oxide has a water absorptionability of 10 to 40 [g/g].
 7. The resin composition according to claim2, wherein the water-absorbing modified polyalkylene oxide has aproportion of water-soluble component of 5 to 30% by mass.
 8. The resincomposition according to claim 3, wherein the water-absorbing modifiedpolyalkylene oxide has a proportion of water-soluble component of 5 to30% by mass.
 9. The resin composition according to claim 2, wherein thethermoplastic resin is an ethylene/vinyl acetate copolymer, anethylene/acrylic acid copolymer, an ethylene/ethyl acrylate copolymer ora combination thereof.
 10. The resin composition according to claim 3,wherein the thermoplastic resin is an ethylene/vinyl acetate copolymer,an ethylene/acrylic acid copolymer, an ethylene/ethyl acrylate copolymeror a combination thereof.
 11. The resin composition according to claim4, wherein the thermoplastic resin is an ethylene/vinyl acetatecopolymer, an ethylene/acrylic acid copolymer, an ethylene/ethylacrylate copolymer or a combination thereof.